The required gauge length (between 30 to 120mm) is to be set by adjusting the upper knife edges and the scales.
Hold the test specimen in the upper and lower jaw of Tensile / Universal Testing Machine.
Position the Extensometer on the specimen. Position Upper clamp to press upper knife on the specimen.
The extensometer will now be fixed to the specimen by spring pressure. Set zero on both the dial gauges.
Start loading the test specimen and take the reading of load on the machine at required elongation or the elongation at required load.
For better accuracies mean of both dial gauge readings should be taken as elongation